Why co-pilots can't eat together before getting on a flight

Believe it or not, despite getting set to fly in very close proximity to one another, pilots cannot eat with one another before they are due to take off.

The reason for this is so that the pilots don't get poisoned or sick while flying the plane, and if one does, then at least the other can fly.

So, in order to avoid any disasters mid-flight, the pilots must not sit down to the same meal before getting on the plane - if they want to visit the same restaurant, they must do so at least an hour apart, or opt to eat at totally different locations.